I changed a 75W bulb into a 20W Led bulb.
At nigth i notized the bulb glows faintly, but clearly visible through the milkglass cover (its a lamp outside my front door) even it is not switched on.
I suspected leakage from a faulty switch or cable.
But leakage resisistance was unmeasurable high.
Next i measured the current, 4 uA !
Gotta be capacitive coupling, i have no other explanation, less than 100pF seem to be enough for that bulb, truely amazing
At nigth i notized the bulb glows faintly, but clearly visible through the milkglass cover (its a lamp outside my front door) even it is not switched on.
I suspected leakage from a faulty switch or cable.
But leakage resisistance was unmeasurable high.
Next i measured the current, 4 uA !
Gotta be capacitive coupling, i have no other explanation, less than 100pF seem to be enough for that bulb, truely amazing
There are a few threads you might want to have a look at, handling this issue.
Here is one of them:
Hugo
Here is one of them:
Hugo
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It does not bother me since it turned out that there is nothing wrong with the cabling.
But i find it truely amazing that, considering the truely low capacitively coupled power of much less than 1mW,
could produce ligth at all.
But i find it truely amazing that, considering the truely low capacitively coupled power of much less than 1mW,
could produce ligth at all.
Modern LED's can be amazingly efficient. I have some small red LED's that are just visible in the dark with something like an 8.2meg resistor and a 9 volt battery.
Yours could well be capacitive coupling, perhaps the cable runs along side another.
One other random thought, is the switch carbonised internally from switching traditional higher wattage bulbs? That may not show on a meter but might allow microscopic current to 'track' along the carbon. Try undoing one wire on the switch... obviously isolate the switch first... and then see if the bulb is dark or not.
I had an opposite sort of issue with several wall light switches and low current LED bulbs flickering and the switch simply not seeming to work. To add insult to injury I opened them all and cleaned them and that made them ten times worse. In disgust I replaced them all and noticed some spec sheets now mention 'suitable for low current.... etc etc' so that may be a known issue. Some of them were heavily discoloured on the white plastic.
Yours could well be capacitive coupling, perhaps the cable runs along side another.
One other random thought, is the switch carbonised internally from switching traditional higher wattage bulbs? That may not show on a meter but might allow microscopic current to 'track' along the carbon. Try undoing one wire on the switch... obviously isolate the switch first... and then see if the bulb is dark or not.
I had an opposite sort of issue with several wall light switches and low current LED bulbs flickering and the switch simply not seeming to work. To add insult to injury I opened them all and cleaned them and that made them ten times worse. In disgust I replaced them all and noticed some spec sheets now mention 'suitable for low current.... etc etc' so that may be a known issue. Some of them were heavily discoloured on the white plastic.
This is a well known phenomenon and is usually mitigated in decently designed products by using resistors in parallel to the LEDs. About 1 MOhm should do.
It makes sense, LEDs emit light in direct proportion to current, so any current at all is enough to generate light. We're used to incandescent lights, which take a significant fraction of their full on power to heat up the filament hot enough to glow.
Given the ratio between the brightness of sunlight and moonlight is something around 100000:1, the human eye is well capable of seeing an efficient LED illuminate at < 1/1000th of its nominal current (at night at least). 15pF is enough to leak 1µA for 240V mains - certain switching circuits for multiple switches controlling one light will have a high capacitance and thus significant leakage current well in excess of 15pF: https://matthews.sites.wfu.edu/courses/p230/switches/SwitchesTut.html
It gets worse. If you dig up the regulations on leakage capacitance for mains transformers, a somewhat excessive 3 nF is permitted between primary and secondary, which can be clearly felt as a throbbing sensation by some people.
Experiment: hold the metal case of some electronics that do this while charging on a 2-pin USB charger, and see if you can get a 5mm LED to light up. You can probably get it to light up between yourself and another person. Lots of variations can be tried.
Experiment: hold the metal case of some electronics that do this while charging on a 2-pin USB charger, and see if you can get a 5mm LED to light up. You can probably get it to light up between yourself and another person. Lots of variations can be tried.
It's starting to approach uncle Fester's electric abilities 😉
https://en.m.wikipedia.org/wiki/Uncle_Fester
https://en.m.wikipedia.org/wiki/Uncle_Fester
Uncle Fester was one of my favourites and probably was my inspiration into electronics. What do kids have today for inspiration? I know it’s a scary question to ask 🙂
That's a new one. And the guy actually looks scary ... Iranian Engineering School background, lovely touch
You haven't seen him before? I remember his first video! It seem he's been around forever with the same schtick. I used the same model ESD gun to debug a problem device about 25 years ago. The problem ended up being in software, but it was fun playing with the gun, and I managed NOT to shock myself.
I have this 60 cm LED rail light in the kitchen , which glows a bit in the dark too.
Leakage current ? But there is a circuit between the 230V and the LEDs , so the leakage goes through it ?
Even weirder things with white LEDs , holding them on one connection , lights them up too. I cannot explain it.
Leakage current ? But there is a circuit between the 230V and the LEDs , so the leakage goes through it ?
Even weirder things with white LEDs , holding them on one connection , lights them up too. I cannot explain it.
Had this too a few times and the first time I thought it was spooky. Also with wires pulled from the switch (everyone suspects the switch at first) sometimes even with slightly brighter light. Moving the hand in the vicinity of the LED lamp can make a difference. Capacitive coupling coupled with sensitive/efficient LEDs. It would not surprise me that the LED possibly glows from RF/electrosmog in the air too.
Another one is that switches die the year after the LED armatures are installed. The now capacitive load is detrimental for the switch.
The question then arises what was exactly gained. The power bill does not show much of a difference, the LED lamp also can go kaput and the switches also may need replacement 🙂
Another one is that switches die the year after the LED armatures are installed. The now capacitive load is detrimental for the switch.
The question then arises what was exactly gained. The power bill does not show much of a difference, the LED lamp also can go kaput and the switches also may need replacement 🙂
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If the wall switch illuminated,you can't use led lamp.
Otherwise it will flicker when the switch is off.
Neon lamp inside wall switch is a capacitance coupling.
I had to remove illumination to stop led lamp flickering.
Otherwise it will flicker when the switch is off.
Neon lamp inside wall switch is a capacitance coupling.
I had to remove illumination to stop led lamp flickering.
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